Laboratory power supply 0-30V 3A, -/+5V

Methods:
All boards were made in thermal transfer method after printing on coated paper and imprinting. It is important not to forget to imprint the boards.

Power supply:

• schema of power supply 30V/3A: Schema + elements
• schema of power supply -/+5V/1A: Schema + elements
• connection of more accurate potentiometers Schema + elements

The current regulation is 0,002-3A and tension 0-30V. The transformer used was taken from a rectifier. It had burnt winding. The transformer was disassembled and winded once again at about 24V. Additional auxiliary power supply is a simple symmetrical power supply of a constant voltage equal to -/+5V power from a separate transformer. Its output current is about 1A. It was powered by a separate transformer, which may come from a tape recorder. For a more precise voltage adjustment, an extra potentiometer 1k was added. In the case of current, one coarse works well and does need further adjustment. 2N3055 transistor is on a small radiator, to which there is a possibility of starting a very quiet storm. It was tested for about 30 minutes at a load of about 2A and it was quite warm, but not hot so that a small radiator and a fan together work well.
Measure section:

• voltmeter schema: Schema + elements
• ammeter schema Schema + elements
• schema of power supply for the meters Schema + elements
• schema of plugging of the meters Schema + elements

Chosen range of the voltmeter was up to 20V. In the future it may expand to 200V. The ammeter is very accurate, to three decimal places. Its range is 2A. Both meters are powered by 5V transformer, which was taken from a tape recorder and they are separate galvanically.
Housing and front panel:

• front panel: Front panels

The housing was made at the specific dimensions of sheet one. It was dyed with resistant to scratching spray. The front panel was made before the housing, so that the dimensions were arbitrary. The effect is displayed in the pictures below. The front panel was printed on a colour laser printer, then laminated and glued on double-sided adhesive tape. The mask was made of plexi of 0,5cm thickness. It was milled to the dimensions of the window and darkened by a car foil.
Gallery:






Other projects:

• voltmeter + ammeter [PCB] Woltomierz/amperomierz ICL7107
• power supply 5V for meters ][PCB] Zasilacz 5V do mierników
• symmetrical power supply 5V Pomoc przy tworzeniu PCB na podstawie schematu - archiwum

Link to original thread – Zasilacz laboratoryjny 0-30V 3A, -/+5V

Vermes said:

• schema of power supply 30V/3A: Schema + elements
• schema of power supply -/+5V/1A: Schema + elements
• connection of more accurate potentiometers Schema + elements

• voltmeter schema: Schema + elements
• ammeter schema Schema + elements
• schema of power supply for the meters Schema + elements
• schema of plugging of the meters Schema + elements

• front panel: Front panels

Click to expand...

None of these links works

Alex